1. Field of Invention
The present invention relates generally to methods and apparatuses for applying an endless, annular tread to a tire casing, and more specifically to a method and an apparatus capable of accurately centering such annular tread on such casing.
2. Description of the Related Art
An endless, annular tread similar to the type utilized in the present invention is disclosed in U.S. Pat. No. 3,815,651 to Neal. An annular tread as disclosed in Neal is endless, i.e. the circle of the tread is unbroken. A second patent issued to Neal, U.S. Pat. No. 4,088,521, discloses another annular tread which features shoulder wings.
Annular treads, such as these disclosed in the Neal Patents, have a relaxed diameter less than the inflated diameter of the tire casing. The annular treads must be stretched radially outwardly to be fitted over the tire casing. Machinery directed to this process is disclosed in U.S. Pat. No. 3,976,532 to Barefoot and U.S. Pat. No. 4,036,677 to Marangoni. The operation of the machine disclosed in FIG. 1 is similar to the machine disclosed in U.S. Pat. No. 3,976,532 to Barefoot. Details of elements of the tread-applying machine disclosed in FIG. 1 which are not essential to the present invention have been only briefly discussed. Additional information regarding the operation of such machines may be found in the Barefoot Patent.
In order to achieve good tire performance, it is important that the annular tread be accurately centered on the tire casing. The present invention is an apparatus and a method for locating the equatorial plane of a tire casing or wheel and accurately positioning an annular tread on the casing.